Randomly Commands 16.0AFR

[30thta436]

a 2004 C5 will randomly command 16.0 AFR while driving, and I don't know why. Any ideas?

Tune and Log attached. Happens at 12:39 on the attached log

[blindsquirrel]

https://forum.hptuners.com/showthrea...rmal-operation

[Hondaeater]

Hmm.

[santacruz4]

I am currently dealing with the problem. I have my cats and rear o2s gone also. this is pulled from a post comment from 5FDP.
It's not a glitch, it's a cat test.

You will also notice that the commanded AFR goes to that 16.00, then drops to 13.XX right after and back to stoich.

This happens when you remove the rear o2 sensors from the vehicle. HP Tuner itself can not disable this test. Everytime I have run into this issue you have to plug the rear o2 sensors back into the harness so the circuits are not left open and just disable all the codes.

Must be an older log compared to the tune file. You do go full throttle and commanded AFR stays at 14.68 but the tune shows it should be dropping to around 12.0.

Also read this as a potential fix from CancerJCC

Instead of having your rear O2's set to "3 - No error reported" and the SES box unchecked set them all to "2- No MIL Light" with the SES box unchecked. I read another post somewhere and this took care of it for me. I also would get 16.00 commanded at low RPM. The other poster said it had to do with lean cruise.

For you other guys this might work as well but I know for sure Tony and I share the same PCM's.

[04silverado6.0]

I have successfully turned this off on an 04 silverado. Still trying to find the parameters on other os.

[04silverado6.0]

You can try this and report back how it does. If it does not work on write cal then a write entire may be needed.